<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Star Sky</title>
<style>
html, body {
margin: 0;
padding: 0;
width: 100%;
height: 100%;
background: #001122;
/*svg 标签是内联元素，防止撑满后会有滚动条出现*/
line-height: 0;
font-size: 0;
}
</style>
</head>
<body>
<svg width="100%" height="100%"
viewBox="-400 -300 800 600"
preserveAspectRatio="xMidYMid slice">
<!-- 一颗星 -->
<defs>
<polygon id="star" points="0 -10 2 -2 10 0 2 2 0 10 -2 2 -10 0 -2 -2" fill="white"></polygon>
</defs>
<g id="real">
<!-- 群星 -->
<g id="star-group">
<!-- 通过 JS 填充群星 -->
</g>
<!-- 月亮 -->
<g id="moon-group" transform="translate(0 50)">
<!-- 通过蒙版（mask）绘制弯月 -->
<mask id="moon-mask">
<circle cx="-250" cy="-150" r="100" fill="white"></circle>
<circle cx="-200" cy="-200" r="100" fill="black"></circle>
</mask>
<circle cx="-250" cy="-150" r="100" fill="yellow" mask="url(#moon-mask)"></circle>
</g>
<!-- 灯塔 -->
<g id="light-tower" transform="translate(250, 0)">
<defs>
<linearGradient id="tower" x1="0" y1="0" x2="1" y2="0">
<stop offset="0" stop-color="#999"></stop>
<stop offset="1" stop-color="#333"></stop>
</linearGradient>
<radialGradient id="light" cx="0.5" cy="0.5" r="0.5">
<stop offset="0" stop-color="rgba(255, 255, 255, .8)"></stop>
<stop offset="1" stop-color="rgba(255, 255, 255, 0)"></stop>
</radialGradient>
<!-- 通过裁切（clipPath）绘制灯光 -->
<clipPath id="light-mask">
<polygon transform="rotate(10)" points="0 0 -300 -15 -300 15">
<animateTransform
attributeName="transform"
attributeType="XML"
type="rotate"
from="0"
to="360"
dur="10s"
repeatCount="indefinite">
</animateTransform>
</polygon>
<circle cx="0" cy="0" r="2"></circle>
</clipPath>
</defs>
<!-- 塔柱 -->
<polygon points="0 0 5 50 -5 50" fill="url(#tower)"></polygon>
<!-- 灯光 -->
<ellipse cx="0" cy="0" rx="300" ry="100" clip-path="url(#light-mask)" fill="url(#light)"></ellipse>
</g>
</g>
<!-- 倒影 -->
<g id="reflact" transform="translate(0 50)" mask="url(#reflact-mask)">
<defs>
<linearGradient id="gradient" x1="0" y1="0" x2="0" y2="1">
<stop offset="0" stop-color="rgba(255,255,255,.3)"></stop>
<stop offset="0.5" stop-color="rgba(255,255,255,0)"></stop>
</linearGradient>
<mask id="reflact-mask">
<rect x="-800" y="0" width="1600" height="400" fill="url(#gradient)"></rect>
</mask>
</defs>
<use xlink:href="#real" transform="scale(1, -1) translate(0 -50)"></use>
</g>
<!-- 地平线 -->
<line x1="-400" y1="50" x2="400" y2="50" ></line>
</svg>
</body>
<script>
/* jshint browser: true */
const SVG_NS = 'http://www.w3.org/2000/svg';
const XLINK_NS = 'http://www.w3.org/1999/xlink';
const paper = document.querySelector('svg');
const defs = document.querySelector('svg defs');
const starRef = document.getElementById('star');
const starGroup = document.getElementById('star-group');
let starCount = 500;
renderStar();
function use(origin) {
const useTag = document.createElementNS(SVG_NS, 'use');
useTag.setAttributeNS(XLINK_NS, 'xlink:href', '#' + origin.id);
return useTag;
}
function random(min, max) {
return min + (max - min) * Math.random();
}
function renderStar() {
let opacitV, transV, scaleV;
let star;
while (starCount--) {
opacitV = random(0.1, 0.4);
transV = random(-400, 400) + ',' + random(-300, 50);
scaleV = random(0.1, 0.6);
star = use(starRef);
star.setAttribute('opacity', opacitV);
star.setAttribute('transform', 'translate(' + transV + ') scale(' + scaleV + ')');
starGroup.appendChild(star);
}
}
</script>
</html>Tips: 参考 techird 老师主讲的课程 《走进SVG 之 图形引用、裁切和蒙版示例》